Just use regular chatter code but don't use class "oe_chatter" if you want to show chatter on popup. This is the code

<record id="your_id" model="ir.ui.view">

    <field name="name">Your Model Name</field>

    <field name="model">your.model</field>

    <field name="arch" type="xml">

        <form>

            <sheet>

                <group>

                    <field name="name" required="1"/>

                </group>                

            </sheet>

            <!-- don't use class="oe_chatter" -->

            <div>

                <field name="message_follower_ids" widget="mail_followers"/>

                <field name="activity_ids" widget="mail_activity"/>

                <field name="message_ids" widget="mail_thread"/>

            </div>

        </form>

    </field>

</record>